The purpose of this project is to further define through longitudinal study of human subjects the specific cellular immune responses of patients with congenital CMV infection and of young women during pregnancy and the postpartum period. In the former group we will examine the hypothesis that alterations of specific cellular immunity are associated with both the persistence of infection and occurrence of progressive deterioration. In the latter group (mothers) we will determine whether specific cell mediated immunity as measured by antigen stimulated lymphokine production and CMV specific responder cell frequency is a significant determinant of virus excretion during pregnancy and the postpartum interval or of transmission of CMV to offspring.